Detailed Solution:

Grafting is a horticultural technique where parts of two plants are joined to grow as one. The rooted plant, known as the stock, provides the root system, while the detached part to be grafted, the scion, forms the shoot system. In this context:

1. Root: The root is the underground part of the plant and provides anchorage and absorbs nutrients. It is not grafted onto the stock; rather, it is part of the stock itself.
2. Scion: The scion is a detached shoot or bud that is grafted onto the stock. It develops into the upper part of the plant, including stems, leaves, flowers, and fruits.
3. Stem: While stems can be part of a graft, the question asks specifically about the part "grafted onto" a stock. The stem itself isn't the standard part grafted; the scion includes the stem.
4. Leaf: A leaf cannot be grafted directly onto a stock. Grafting involves joining tissues capable of forming vascular connections, which leaves do not have on their own.

Therefore, the part of a plant that is grafted onto a stock is the scion.

Final Answer: Scion

Detailed Solution:

Pioneer species are the first organisms to colonize a barren or disturbed environment. In aquatic ecosystems, these initial colonizers play a crucial role in establishing life and preparing the habitat for other organisms.

1. Fungi: Fungi are typically decomposers in terrestrial ecosystems. While some may exist in aquatic environments, they are not considered primary colonizers.
2. Algae: Algae, especially cyanobacteria, are crucial primary producers in aquatic habitats. They perform photosynthesis, generating energy and organic matter while surviving harsh conditions. They are capable of colonizing nutrient-poor environments and creating a base for more complex food webs.
3. Bryophytes: Bryophytes include mosses and liverworts and are predominantly terrestrial plants. They require moist environments and are not typically the first colonizers in aquatic habitats.
4. Lichens: Lichens are symbiotic associations of fungi and algae or cyanobacteria. They are mainly found in terrestrial environments and are not common pioneers in aquatic settings.

Therefore, the pioneer species in aquatic habitats are Algae.

Final Answer: Algae

Detailed Solution:

The average heart rate is the number of times the heart beats per minute. This rate is not constant and can vary due to different factors.

1. Average Resting Heart Rate: For a healthy adult, the average resting heart rate is about 72 beats per minute. However, this can range from 60 to 100 beats per minute.
2. Factors Affecting Heart Rate:
   • Physical Activity: Exercise or stress can increase heart rate.
   • Age: Infants and young children have higher heart rates than adults.
   • Health Status: Conditions like bradycardia (slow heart rate) or tachycardia (fast heart rate) can cause significant deviations from the normal range.
3. Average Heart Rate Calculation: The given options represent a range. However, 72 is the typically accepted average heart rate for adults.

Therefore, a person has an average of 72 heartbeats per minute.

Final Answer: 72 beats per minute

Detailed Solution:

Heme is a prosthetic group present in hemoglobin, a protein in red blood cells responsible for oxygen transport. Its role is critical for efficient oxygen delivery to tissues.

1. Heme Composition: Heme is made of an iron atom bound to a porphyrin ring. The iron atom is the site where oxygen binds.
2. Oxygen Binding:
   • When red blood cells pass through the lungs, the iron in the heme group binds to oxygen.
   • The oxygenated hemoglobin carries oxygen through the bloodstream.
3. Oxygen Release: In tissues where oxygen is needed for cellular respiration, the oxygen detaches from hemoglobin and is used by cells for energy production.
4. Other Options:
   • While hemoglobin also binds carbon dioxide, the binding is not specifically due to the heme group, and its main function remains oxygen transport.
   • Heme contributes to the overall structure of hemoglobin but is not the only component involved in its stability.
   • Heme doesn't act as an enzyme; rather it is a prosthetic group within the functional protein hemoglobin.

Therefore, the primary role of heme in hemoglobin is the transport of oxygen.

Final Answer: Transport of oxygen

Detailed Solution:

Aerobic respiration is the process by which cells break down glucose in the presence of oxygen to produce energy in the form of ATP. It is the most efficient form of energy production.

1. Stages of Aerobic Respiration: Aerobic respiration comprises three main stages:
   • Glycolysis: This initial stage occurs in the cytoplasm and breaks down glucose into pyruvate, generating 2 ATP molecules.
   • Krebs Cycle (Citric Acid Cycle): This cycle occurs in the mitochondria and further oxidizes pyruvate, generating 2 ATP molecules.
   • Electron Transport Chain (Oxidative Phosphorylation): This final stage, also in mitochondria, uses the products of the previous stages to produce the bulk of ATP. It generates approximately 32 ATP molecules.
2. Total ATP Production: The total ATP yield from aerobic respiration can be calculated by summing up the ATP produced in each stage:

   Total ATP = ATP (Glycolysis) + ATP (Krebs Cycle) + ATP (Electron Transport Chain)

   Total ATP = 2 + 2 + 32 = 36 ATP

Therefore, the total amount of ATP produced in aerobic respiration is 36 ATP.

Final Answer: 36 ATP

Detailed Solution:

This question requires distinguishing between two groups of scientists and their contributions to the understanding of DNA.

1. Avery, McLeod, and McCarty:
   • These scientists conducted experiments in the 1940s to prove that DNA is the genetic material, not proteins.
   • They did this using bacterial transformation experiments where they isolated and purified DNA which could cause transformation.
   • They established that the DNA carries the genetic information in cells. However, they did not determine how DNA replicates.
2. Meselson and Stahl:
   • These scientists in the 1950s used density gradient centrifugation to determine how DNA is replicated.
   • They used E. coli bacteria, grown in different forms of Nitrogen, to track the incorporation of this heavy nitrogen in successive generations of bacteria, and thus concluded that DNA replication is semi-conservative
   • This semi-conservative model revealed that each new DNA double helix contains one old (parental) strand and one new strand.
3. Analyzing Statements:
   • Statement 1 is incorrect because Avery, McLeod, and McCarty discovered DNA as the genetic material but did not determine its replication method.
   • Statement 2 is correct because Meselson and Stahl provided the evidence for the semi-conservative nature of DNA replication.

Therefore, statement 2 is correct while statement 1 is incorrect.

Final Answer: Statement 2 is correct, Statement 1 is incorrect

Detailed Solution:

A thermal cycler, or PCR machine, is an instrument used in molecular biology for the controlled heating and cooling of samples, enabling DNA amplification through the Polymerase Chain Reaction (PCR).

1. Thermal Cycler Function: The thermal cycler precisely controls the temperature of samples over time, following a specific cycle of heating and cooling.
2. PCR and its Steps: PCR involves the following steps:
   • Denaturation: The DNA sample is heated to 94 - 96°C, breaking the hydrogen bonds and separating the double strands.
   • Annealing: The temperature is lowered (typically to 50 - 65°C), allowing primers to bind to specific DNA sequences.
   • Extension: The temperature is increased to 72°C, the optimal temperature for DNA polymerase to synthesize new DNA strands using the primers.
3. Other Options:
   • While temperature control is a vital function, the main purpose of the cycler is to achieve cycling which is essential for PCR.
   • Protein synthesis and RNA transcription require different processes and instruments.

Therefore, a thermal cycler/stabilizer is primarily used for DNA amplification (PCR).

Final Answer: DNA amplification (PCR)

Detailed Solution:

Neanderthals were an extinct species of archaic humans who lived in Europe and parts of Asia. The archaeological record provides important insights into their culture and lifestyle.

1. Lascaux Cave, France:
   • While primarily famous for its Paleolithic cave paintings, there is some debate about the presence of Neanderthal artifacts within this location. However, its significance in understanding the broader Paleolithic landscape is crucial.
2. Altamira Cave, Spain:
   • Altamira is well known for its prehistoric art, and associated artifacts. While debated if the makers were Neanderthals, its relation to ancient cultures in the area is important.
3. Shanidar Cave, Iraq:
   • This site is important for discovering Neanderthal skeletal remains and evidence of intentional burial practices. The evidence of rituals provides important understanding of their behavior.

Therefore, Neanderthal remains and artifacts have been found at all of the above sites.

Final Answer: All of the above

Detailed Solution:

Plant hormones play vital roles in regulating plant growth and development, including fruit size.

1. Auxin: Auxins promote cell elongation and are involved in plant growth, but they are not the primary hormone used to enhance fruit size.
2. Gibberellin:
   • Gibberellins are a group of hormones that promote cell elongation and cell division.
   • They enhance fruit size by increasing the cell size, leading to larger fruits.
   • They are widely used in horticulture for increasing the size of fruits like grapes and apples and promoting stem elongation and seed germination.
3. Cytokinin: Cytokinins are involved in cell division, shoot development, and overall plant growth. They are not the main hormones in fruit size enhancement.
4. Ethylene: Ethylene is a gaseous hormone involved in fruit ripening, senescence, and stress responses. It does not play a role in fruit size enhancement.

Therefore, Gibberellin is the hormone primarily used for increasing the size of fruit.

Final Answer: Gibberellin

Detailed Solution:

Hydrolysis is the process of breaking down large molecules into smaller ones by adding water. Carbohydrates are classified based on their complexity.

1. Polysaccharides: Polysaccharides are complex carbohydrates formed from many monosaccharide units linked together. They can be hydrolyzed into disaccharides and monosaccharides.
2. Disaccharides: Disaccharides are composed of two monosaccharide units linked by glycosidic bonds. They can be hydrolyzed into their constituent monosaccharides.
3. Monosaccharides:
   • Monosaccharides are simple sugars that cannot be further broken down by hydrolysis.
   • They are the smallest carbohydrate units, such as glucose, fructose, and galactose.
4. Oligosaccharides: Oligosaccharides consist of a few monosaccharide units. They can be hydrolyzed into their constituent monosaccharides.

Therefore, Monosaccharides cannot be further hydrolyzed.

Final Answer: Monosaccharides

Detailed Solution:

Respiration, the process of generating ATP, has different mechanisms across organisms depending on their cellular structure and organelles.

1. Prokaryotes:
   • Prokaryotic cells, such as bacteria, lack membrane-bound organelles like mitochondria.
   • Instead, they utilize their plasma membrane for respiratory processes.
   • The plasma membrane in prokaryotes hosts enzymes for the electron transport chain and for oxidative phosphorylation.
2. Eukaryotes: Eukaryotic cells have mitochondria, which are the primary sites for ATP production via cellular respiration. The plasma membrane does not perform significant respiratory roles.
3. Viruses: Viruses are not cellular organisms and lack metabolic machinery. They are completely dependent on host cells for energy production.
4. Fungi: Fungi are eukaryotic organisms, and cellular respiration occurs in mitochondria.

Therefore, Prokaryotes utilize the plasma membrane for respiration.

Final Answer: Prokaryotes

Detailed Solution:

An electrocardiogram (ECG) records the electrical activity of the heart. Specific intervals on the ECG tracing correspond to different physiological events.

1. P wave: The P wave represents atrial depolarization. Its duration is shorter than the PR interval.
2. QRS complex: The QRS complex represents ventricular depolarization and is much shorter in duration.
3. PR Interval:
   • The PR interval represents the time it takes for an electrical impulse to travel from the sinoatrial (SA) node through the atria, AV node, and into the ventricles.
   • The typical duration of the PR interval is 0.12 – 0.20 seconds, making 0.16 seconds is within this normal range.
   • It reflects conduction through the AV node and the delay that allows the ventricles to fill with blood.
4. T wave: The T wave represents ventricular repolarization and has its own distinct duration.

Therefore, 0.16 seconds corresponds to the duration of the PR interval.

Final Answer: PR interval

Detailed Solution:

Plant hormones are key regulators of plant growth and development, including fruit size and yield.

1. Auxin: Auxin promotes cell elongation and is involved in plant growth, but it is not the primary hormone for fruit size enhancement.
2. Gibberellin:
   • Gibberellins are plant hormones that promote cell elongation and division.
   • They enhance fruit size by increasing the size of the cells within the fruit.
   • They are used in agriculture to improve fruit quality and yield by promoting fruit enlargement.
3. Cytokinin: Cytokinins promote cell division and are important for shoot development. They do not have as significant impact on fruit size.
4. Ethylene: Ethylene is involved in fruit ripening and senescence. It does not significantly increase fruit size.

Therefore, Gibberellin is used to increase the size of fruit.

Final Answer: Gibberellin

Detailed Solution:

The urinary bladder is a muscular organ that stores urine and has a layered structure. Understanding these layers is crucial for studying its function and related disorders.

1. Mucosa:
   • This is the innermost layer, comprised of transitional epithelium and lamina propria.
   • Transitional epithelium allows the bladder to stretch and accommodate varying urine volumes.
   • The lamina propria, a layer of connective tissue, supports the epithelium.
2. Submucosa:
   • The submucosa consists of connective tissue and provides structural support to the bladder.
   • It contains blood vessels and nerves.
3. Muscularis:
   • The muscularis is composed of the detrusor muscle, responsible for bladder contraction and relaxation.
   • It enables the bladder to store and expel urine.
4. Serosa/Adventitia:
   • This is the outermost layer of the bladder.
   • It provides protection to the bladder and connects it with surrounding tissues.

Therefore, the urinary bladder layers are: Mucosa, Submucosa, Muscularis, and Serosa/Adventitia.

Detailed Solution:

The fundamental frequency is the lowest frequency of a vibrating object or system.

1. Fundamental Frequency Formula: The fundamental frequency f for an open organ pipe is given by the formula:

   f = v / λ

   where:
   • v is the speed of sound in the medium
   • λ is the wavelength of the fundamental mode
2. Wavelength for Open Pipe: For an open pipe, the fundamental mode corresponds to a wave where there are antinodes at both ends of the pipe and a node in the middle. This leads to the length of the pipe L being half the wavelength. Therefore:

   λ = 2L

3. Substituting Wavelength: Substituting the value of λ in the fundamental frequency formula:

   f = v / (2L)

Therefore, the fundamental frequency of an open organ pipe is v/2L.

Final Answer: v/2L

Detailed Solution:

The angular frequency describes how fast a system is oscillating. It relates to the period of oscillation.

1. Restoring Force in SHM: The restoring force in a simple harmonic oscillator (SHM), like a spring-mass system, is given by:

   F = -kx

   where:
   • F is the restoring force
   • k is the spring constant
   • x is the displacement from equilibrium.
2. Using Newton's Second Law: According to Newton's second law, F = ma, where a is the acceleration. Since acceleration is the second derivative of displacement, a = d²x/dt² = ẍ. Combining this we get:

   m ẍ + kx = 0

3. Angular Frequency Formula: This differential equation describes simple harmonic motion and the solution is of the form: x = Acos(ωt + ϕ), where angular frequency ω is:

   ω = √(k/m)

Therefore, the angular frequency of a simple harmonic oscillator is √(k/m).

Final Answer: √(k/m)

Detailed Solution:

Newton's Law of Cooling describes the rate at which a body's temperature changes with time.

1. Newton's Law of Cooling: This law states that the rate of cooling is proportional to the temperature difference between the body and its surroundings.

   Rate of cooling = k (∆T)

   where:
   • Rate of cooling is the rate of change in temperature,
   • k is the proportionality constant,
   • ∆T is the temperature difference (excess temperature).
2. Given Values: We are given the following:
   • Rate of cooling = 0.2 °C/min
   • ∆T = 20 °C
3. Solving for k: Substituting the given values into the equation:

   0.2 °C/min = k (20 °C)

   k = 0.2 °C/min / 20 °C

   k = 0.01 min⁻¹

Therefore, the proportionality constant k is 0.01 min⁻¹.

Final Answer: 0.01 min⁻¹

Detailed Solution:

The linear velocity of a rotating object is the speed at which a point on the rim of the object is moving.

1. Linear Velocity Formula:

   v = rω

   where:
   • v is linear velocity,
   • r is the radius of the circle,
   • ω is the angular velocity.
2. Radius Calculation: The diameter of the wheel is given as 20 cm. The radius (r) is half the diameter:

   r = diameter / 2 = 20 cm / 2 = 10 cm = 0.1 m

3. Angular Velocity Calculation: The wheel is rotating at 600 revolutions per minute (rpm). To convert rpm to radians per second:

   ω = 2πf = 2π (rpm / 60)

   ω = 2π (600/60) = 2π (10) = 20π rad/s

4. Substituting Values: Substituting the values of r and ω into the linear velocity formula:

   v = rω = 0.1 m * 20π rad/s

   v ≈ 0.1 * 20 * 3.14 = 6.28 m/s

Therefore, the linear velocity of the particle at the rim is approximately 6.28 m/s.

Final Answer: 6.28 m/s